Anthrapyridone compound, water-based magenta ink composition, and method of ink-jet recording

ABSTRACT

The ink composition comprises as its coloring matter component a water-based magenta composition containing anthrapyridone compound represented by the formula ( 1 ): 
                 
 
wherein R represents hydrogen atom or methyl group; X represents phenyl group, phenoxy group or halogen atom; and n is an integer of 1 to 4, or salt thereof.

FIELD OF THE INVENTION

The present invention relates to a novel sulfonic acid derivative ofanthrapyridone compound or its salt, a water-based magenta inkcomposition for ink-jet recording comprising said compound, and anink-jet recording method using said composition.

BACKGROUND OF THE INVENTION

As a recording method using an ink-jet printer, various kinds of diverseink jetting systems have been developed, and for recording in thesesystems, ink droplets are generated and deposited to various recordingmaterials (paper, film, cloth etc.).

A recording method via an ink-jet printer has characteristics such thatno sound is produced since there is no contact between a recording headand a recording material and this method can print on a variety ofsubstrates such as a substrate having uneven surfaces, a substratecomprising a soft material, and a fragile substrate. Recently, ink-jetprinters are spread rapidly since it is easy to reduce their size, toprint with a high speed and to make color prints. They are expected tobe further popularized significantly.

In order to record in color picture or character informations on a colordisplay of a computer via an ink-jet printer, a subtractive mixturemethod with four inks comprising three primary coloring matters ofyellow (Y), magenta (M) and cyan (C) and additionally black (K) isgenerally adopted. To reproduce a subtractive mixed color image asfaithfully as possible by a subtractive mixed color image of red (R),green (G) and blue (B) for CRT displays etc., it is desired thatcoloring matters used, particularly coloring matters used in YMC inks,have hues as near as possible to standard hues of YMC and are as vividas possible. And, an ink composition is requested to be stable for along-period storage and to give prints having a high concentration andexcellent in fastnesses such as water resistance, light resistance, andozone resistance. Prints resulting from recording via an ink-jet printerwill be applied for display such as advertisement in order to broaden anapplication of an ink composition. In such cases, prints will be oftenexposed to light (an electric lamp, a fluorescent lamp, a sunlight andthe like) and an air (containing nitrogen oxide gas, ozone gas and thelike). Thus, an ink composition giving printed images excellent in ozoneresistance is especially requested. Many images printed on coated papersvia an ink-jet printer are faded by ozone. Reason considered is aninteraction between an ozone gas in an air and inorganic substancesand/or polymers applied on coated papers, but it is not correctlyelucidated at present. The present invention relates to a magenta inkamong inks having the above hues.

The application of ink-jet printers is broadened from small printers forOA to large printers for industry, and a chance to expose printsoutdoors is increasing. Thus, the improvement of fastnesses such aswater resistance, light resistance, and ozone resistance is furtherrequested. Among these properties, water resistance is under significantimprovement by coating, together with PVA resin, organic or inorganicfine particles (e.g. cationic polymer, porous silica, alumina sol andspecial ceramics) capable of adsorbing coloring matters in ink, onto thesurface of the paper. In practice, such papers have been commerciallyavailable as various coated papers for ink-jet printing. However, atechnique significantly improving light resistance and ozone resistancehas not been established yet. If prints resulting from printing oncoated papers called as glossy papers are left in a well ventilatedplace, they are faded and discolored. In order to resolve this problem,prints are processed by laminating after printing so as to prevent themfrom fading at present. However, this method has many demerits in time,convenience and cost. To provide a fundamental method for improving theabove problem, the development of a magenta dye which is hardly faded isan important problem.

Representative skeletons of a magenta coloring matter used in awater-based ink for ink-jet recording are xanthene as described inJP-A-54089811 (1979), JP-A-08060053 (1996), JP-A-08143798 (1996) and thelike; and azo having H acid in its skeleton as described inJP-A-61062562 (1986), JP-A-62156168 (1987), JP-A-03203970 (1991),JP-A-07157698 (1995), JP-B-07078190 (1995) and the like. However,xanthene coloring matter have very poor light resistance although theyare very excellent in hue and clarity. While, azo coloring matter havingH acids in their skeletons have poor light resistance and clarityalthough they have good hue and water resistance. As described inJP-A-03203970 (1991), an azo magenta dye excellent in clarity and lightresistance has been developed, but its light resistance is stillinsufficient as compared with dyes having other hues such as a cyan dye,a representative of which is a cupper phthalocyanine dye, a yellow dyeand the like. And, prints resulting from printing with these coloringmatters on glossy papers may be discolored and faded even if they areleft in a well ventilated place.

Further, as a magenta coloring matter excellent in clarity and lightresistance, coloring matters having anthrapyridone skeleton as describedin JP-A-59074173 (1984), JP-A-02016171 (1990) and the like are known,but they do not meet all requirements of hue, clarity, light resistance,water resistance, ozone resistance and a solution stability.

An object of the present invention is to provide a water-based magentaink composition having a hue and clarity suitable for ink-jet recordingand gives prints excellent in fastnesses such as a light resistance, andan ozone resistance.

SUMMARY OF THE INVENTION

The present inventors hardly researched for resolving the aboveproblems. As the result, the present invention was completed. That is,the present invention relates to:

(1) an anthrapyridone compound represented by the formula (1):

wherein R represents hydrogen atom or methyl group; X represents phenylgroup, phenoxy group or halogen atom; and n is an integer of 1 to 4,or a salt thereof;

(2) the anthrapyridone compound as described in (1) wherein n is aninteger of 2 to 4, or the salt thereof;

(3) the anthrapyridone compound as described in (2) wherein X representsphenyl group, or the salt thereof;

(4) an anthrapyridone compound represented by the formula (2):

wherein X represents phenyl group, phenoxy group or halogen atom, or asalt thereof;

(5) an anthrapyridone compound represented by the formula (3):

wherein X represents phenyl group, phenoxy group or halogen atom, or asalt thereof;

(6) an anthrapyridone compound represented by the formula (4):

or a salt thereof;

(7) a water-based magenta ink composition comprising anthrapyridonecompound as described in any one of (1) to (6) or a salt thereof;

(8) a water-based magenta ink composition as described in (7) comprisingwater and a water-soluble organic solvent;

(9) a water-based magenta ink composition as described in (7) or (8),wherein said composition is for ink-jet recording;

(10) an ink-jet recording method, which comprises using the water-basedmagenta ink composition as described in any one of (7) to (9) as the inkin the ink-jet recording way that ink droplets are jetted responding torecording signal to record on a recording material;

(11) an ink-jet recording method, which comprises using the water-basedmagenta ink composition as described in any one of (7) to (9) as the inkand a water-based cyan ink composition comprising a water-soluble metalphthalocyanine coloring matter as a cyan ink in the ink-jet recordingway that ink droplets are jetted responding to recording signal torecord on a recording material;

(12) an ink-jet recording method as described in (10) or (11) whereinthe substrate to be recorded is a polyamide fibrous material and thefibrous material is heat treated after the ink composition is applied;

(13) an ink-jet recording method as described in (10) or (11) whereinthe recording material is an information transmittance sheet;

(14) an ink-jet recording method as described in (13) wherein theinformation transmittance sheet is a surface treated sheet;

(15) an ink-jet printer in which a container containing a water-basedmagenta ink composition as defined in any one of (7) to (9) and acontainer containing a water-based cyan ink composition comprising awater-soluble metal phthalocyanine coloring matter are set.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described in more detail.

The anthrapyridone compound of the formula (1) is obtained by, forexample, the following method. That is, to 1 mole of the compoundrepresented by the formula (6):

is added ethyl benzoylacetate generally in an amount of 1 to 3 moles andthen they are heated in a solvent such as xylene in the presence of acatalytic amount of sodium carbonate or sodium carbonate anhydride at atemperature of generally 130 to 145° C. for a period of generally 2 to10 hours, while water and ethanol produced are removed by azeotropicdistillation with the solvent so that a ring closure is effected,thereby the compound of the formula (7):

is obtained. Then, this compound of the formula (7) is added to fumingsulfuric acid having a concentration of generally 5 to 30% andsulfonated at a temperature of generally 5 to 100° C. for a period ofgenerally 15 minutes to 10 hours, thereby the anthrapyridone compound ofthe formula (1) is obtained.

The novel anthrapyridone compound of the present invention isrepresented by the formula (1). Example of the substituent X on phenoxygroup in the formula (1) includes p-phenyl, o-phenyl, p-phenoxy,p-chloro, o-chloro, p-bromo groups and the like.

Examples of the compound represented by the formula (2) of the presentinvention are set forth below:

The present compound may be in the form of a free acid or a salt. Thesulfonated product of the compound of the formula (2) can be used as afree acid or a salt such as an alkali metal salt, an alkaline earthmetal salt, an alkylamine salt, an alkanolamine salt and an ammoniumsalt. Example of the preferable salt includes alkali metal salts such assodium, potassium and lithium salts; ammonium salt; and alkanolaminesalts such as monoethanolamine, diethanolamine, triethanolamine,monoisopropanolamine, diisopropanolamine and triisopropanolamine salts.

A salt of the sulfonated product of the compound of the formula (2) isprepared by, for example, the following method.

First, a sufonated reaction liquid is added into an iced water, to whichsodium chloride is added to salt out and the reaction product isfiltered, thereby a sodium salt of the sulfonated product of thecompound of the formula (2) is obtained. Then, this sodium salt isdissolved in water and an acid is added to precipitate crystals. Thecrystals are filtered to obtain a coloring matter in a free acid form asa cake. Then, the coloring matter in a free acid form is dissolved orsuspended in water, in which the amine or metal salt mentioned above isadded and dissolved, thereby a desired salt of the sulfonated product ofthe compound of the formula (2) is obtained.

The water-based ink composition of the present invention is obtained bydissolving the above coloring matter component in water, or optionallymixture of water and water-soluble organic solvent. A pH of theresultant ink is preferably about 6 to 10. When the water-based inkcomposition is used in an ink-jet printer, the coloring mattercontaining a minor amount of inorganic substances such as chloride,sulfate and the like of metallic cations is preferably used. As acriterion of a total amount of inorganic substances, a total amount ofsodium chloride and sodium sulfate of at most 1% by mass may bementioned. In order to prepare the coloring matter component containinga minor amount of inorganic substances of the present invention, thecoloring matter component of the present invention may be desaltedaccording to a routine method using a reverse osmosis membrane, a methodcomprising dissolving the coloring matter component in the form of a dryproduct or a wet cake in a mixture of alcohol and water with stirring,filtering and drying, or the like.

The water-based ink composition of the present invention is formulatedas a composition based on water. The coloring matter component of thepresent invention is contained in an amount of preferably about 0.1 to20% by mass, more preferably about 1 to 10% by mass, even morepreferably about 2 to 8% by mass in the water-based ink composition.Further, the water-based ink composition of the present invention maycomprise 0 to 30% by mass of a water-soluble organic solvent and 0 to 5%by mass of ink additives.

The ink composition of the present invention is prepared by adding andmixing the above compound of the present invention and optionally awater-soluble organic solvent, ink additives or the like in water freefrom impurities such as a distilled water and the like. Alternatively,the compound of the present invention may be added and dissolved in amixture of water, a water-soluble organic solvent, ink additives and thelike. If necessary, impurities may be removed by filtering after the inkcomposition is prepared.

Example of the usable water-soluble organic solvent includes C1-C4alkanols such as methanol, ethanol, propanol, isopropanol, butanol,isobutanol, sec-butanol, and tert-butanol; carboxamides such asN,N-dimethylformamide and N,N-dimethylacetamide; lactams such asN-methylpyrrolidin-2-one; cyclic ureas such as1,3-dimethylimidazolidin-2-one and 1,3-dimethylhexahydro pyrimid-2-one;ketones or ketoalcohols such as acetone, methyl ethyl ketone, and2-methyl-2-hydroxypentan-4-one; ethers such as tetrahydrofuran anddioxane; mono-, oligo- or poly-alkylene glycols or thioglycols havingC2-C6 alkylene units such as ethylene glycol, 1,2- or 1,3-propyleneglycol, 1,2- or 1,4-butylene glycol, 1,6-hexylene glycol, diethyleneglycol, triethylene glycol, dipropylene glycol, thiodiglycol,polyethylene glycol, and polypropylene glycol; polyols (triols) such asglycerol and hexane-1,2,6-triol; C1-C4 alkyl ethers of polyhydricalcohols such as ethylene glycol monomethyl ether, ethylene glycolmonoethyl ether, diethylene glycol monomethyl ether, diethylene glycolmonoethyl ether, triethylene glycol monomethyl ether, and triethyleneglycol monoethyl ether; γ-butyrolactone; dimethyl sulfoxide; and thelike. The water-soluble organic solvent may be used in mixture.

Effective water-soluble organic solvent includes N-methylpyrrolidin-2-onand mono-, di- or tri-alkylene glycol having C2-C6 alkylene units,preferably mono-, di- or tri-ethylene glycol, dipropylene glycol,dimethyl sulfoxide and the like, N-methylpyrrolidin-2-on, diethyleneglycol and dimethyl sulfoxide are especially preferably used.

Example of ink additives includes an antiseptic and mildew-proofingagent, a pH controlling agent, a chelating agent, a rust preventive, awater-soluble UV absorber, a water-soluble polymeric compound, a dyesolubilizing agent, a surfactant and the like. Example of an antisepticand mildew-proofing agent includes sodium dehydroacetate, sodiumsorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, sodiumpentachlorophenol and the like. As a pH controlling agent, any compoundcan be used as long as it does not affect an ink composition to beformulated and it can control a pH of an ink composition in the range of6 to 11. Example thereof includes alkanolamines such as diethanolamine,and triethanolamine; alkali metal hydroxides such as lithium hydroxide,sodium hydroxide, and potassium hydroxide; ammonium hydroxide; alkalimetal carbonates such as lithium carbonate, sodium carbonate, andpotassium carbonate; and the like. Example of a chelating agent includessodium ethylendiamine tetraacetate, sodium nitrilotriacetate, sodiumhydroxyethyl ethylendiamine triacetate, sodium diethylenetriaminepentacetate, sodium uramildiacetate and the like. Example of arust preventive includes acid sulfite, sodium thiosulfate, ammoniumthioglycolate, diisopropylammonium nitrite, pentaerythritoltetranitrate, dicyclohexylammonium nitrite and the like. Example of awater-soluble polymeric compound includes polyvinyl alcohol, a cellulosederivative, polyamine, polyimine and the like. Example of awater-soluble UV absorber includes sulfonated benzophenone, sulfonatedbenzotriazole and the like. Example of a dye solubilizing agent includesε-caprolactam, ethylene carbonate, urea and the like. Example of asurfactant includes known surfactants of anionic, cationic or nonionictype.

Example of a recording material applicable to the ink-jet recordingmethod of the present invention includes information transmission sheetsuch as papers and films, fibers, leathers and the like. Preferableinformation transmission sheets are surface treated sheets, specificallysheets having ink receiving layers on the above substrates. The inkreceiving layer is provided by immersing a cationic polymer in thesubstrate or coating the substrate with a cationic polymer, or applyinginorganic fine particles capable of adsorbing a color in an ink such asa porous silica, an alumina sol, and a specific ceramic together with ahydrophilic polymer such as polyvinyl alcohol, polyvinyl pyrrolidone andthe like on a surface of the substrate. A sheet having an ink receivinglayer is generally called as ink-jet exclusive papers (films) or glossypapers (films). For example, these sheets are commercially available asPictorico (Asahi Glass Co., Ltd.), Color BJ Paper and Color BJ Photofilm sheet (both Canon Inc.), Color Image Jet Paper (Sharp Corporation),Superfine exclusive glossy film (Epson Corporation), Pictafine (HitachiMaxell, Ltd.) and the like. Of course, the ink-jet recording method ofthe present invention can be applied to plain papers.

The fibers are preferably polyamide fibers such as nylon, silk, andwool. Woven or non-woven fabric is preferable. The ink composition ofthe present invention is applied to the fibers preferably by an ink-jetrecording method and then fixed under a wet heat condition (for example,about 80 to 120° C.) or a dry heat condition (for example, about 150 to180° C.) so that the color can be fixed within the fibers. The thus-dyedproduct is excellent in clarity, light resistance and laundryresistance.

In order to record on a recording material by the ink-jet recordingmethod of the present invention, for example a container containing theabove water-based magenta ink composition may be set (filled up) in anink-jet printer and then the recording may be made on the substrateaccording to the conventional method. Example of an ink-jet printerincludes a piezo-type printer where a mechanical vibration is employed,a bubble jet (R) type printer where bubbles produced by heating isemployed; and the like.

In the ink-jet recording method of the present invention, thewater-based magenta ink composition of the present invention may becombined with a yellow ink composition, a cyan ink composition andoptionally a black ink composition. When a water-based cyan inkcomposition comprising a water-soluble metal phthalocyanine color isused as a cyan ink composition, a change in color tone before and aftera light resistance test becomes small by combining it with thewater-based magenta ink composition of the present invention. Example ofa metal in a water-soluble metal phthalocyanine coloring matter includescupper, nickel, aluminum and the like, among which cupper is preferable.Example of a water-soluble cupper phthalocyanine coloring matterincludes C.I. Direct Blue 86, C.I. Direct Blue 87, C.I. Direct Blue 199,C.I. Acid Blue 249, C.I. Reactive Blue 7, C.I. Reactive Blue 15, C.I.Reactive Blue 21, C.I. Reactive Blue 71 and the like.

A water-based cyan ink composition comprising a water-soluble metalphthalocyanine coloring matter is, for example, prepared according tothe method of preparing the water-based magenta ink composition of thepresent invention and poured into a container, and the container is setin a predetermined position in an ink-jet printer similarly to thecontainer containing the water-based magenta ink composition of thepresent invention.

The water-based ink composition of the present invention has a clearmagenta color, for which a color tone over a wide visible light rangecan be obtained by using it together with other yellow and cyan inks. Byusing together with yellow, cyanine and black inks excellent in ozoneresistance, light resistance and water resistance, prints excellent inlight resistance, water resistance and especially ozone resistance canbe obtained.

EXAMPLES

The present invention will be described by referring to the followingexamples. All parts and percentages referred to herein are by weightunless otherwise indicated.

Example 1

(1) Into 210 parts of xylene, 67.5 parts of the compound of the formula(8):

1.4 part of sodium carbonate and 67.2 parts of ethyl benzoylacetate weresuccessively charged and heated. They were reacted at a temperature of140 to 143° C. for 4 hours, while water and ethanol produced weredistilled away together with xylene. After the reaction was completed,the resultant product was cooled with water, to which 175 parts ofmethanol was added, stirred for 30 minutes, filtered, washed with 400parts of methanol and hot water successively and dried, thereby 76.1parts of the compound of the formula (9) was obtained as needle-likecrystals of a red color.

(2) To 142.3 parts of 96.6% sulfuric acid was added 207.7 parts of 30.6%fuming sulfuric acid while cooling with an iced water to prepare 350parts of 12% fuming sulfuric acid. Then, 42.7 parts of the compound ofthe formula (9) obtained in the above (1) was added to fuming sulfuricacid at 20 to 40° C. over 30 minutes. Then, they were heated at 60 to70° C. for two hours with stirring to complete the sulfonation. Next,the above reaction liquid was added in an iced water in such an amountthat a total liquid volume was 1000 parts. The reaction was filtered toremove a minor amount of insoluble matter. 200 parts of sodium chloridewas added to the mother liquid while stirring and they were stirred forone hour. The resultant precipitates were filtered and washed with 50parts of a water-based 20% brine solution to obtain a wet cake.

This cake was again stirred with water in such an amount that a totalliquid volume was 1000 parts. 200 parts of sodium chloride was added tothe liquid and then stirred for 3 hours. The resultant precipitates werefiltered, washed with 100 parts of a water-based 20% brine solution anddried, thereby 65.0 parts of a sodium salt of the compound of theformula (4) as crystals of a bright red color.λ_(max)=528.2 nm (in aqueous solution)

solubility in water=100 g/L or higher

Example 2

(1) Into 180 parts of xylene, 43.4 parts of the compound of the formula(10):

0.9 part of sodium carbonate and 43.3 parts of ethyl benzoylacetate weresuccessively charged and heated. They were reacted at a temperature of138 to 141° C. for 6 hours, while water and ethanol produced weredistilled away together with xylene. After the reaction was completed,the resultant product was cooled with water, to which 200 parts ofmethanol was added, stirred for 30 minutes, filtered, washed with 250parts of methanol and hot water successively and dried, thereby 50.3parts of the compound of the formula (11) was obtained as needle-likecrystals of a yellowish red color.

(2) To 52.9 parts of 96.6% sulfuric acid was added 47.1 parts of 31.7%fuming sulfuric acid while cooling with an iced water to prepare 100parts of 6.5% fuming sulfuric acid. Then, 12.2 parts of the compound ofthe formula (11) obtained in the above (1) was added to the fumingsulfuric acid at 15 to 20° C. over one hour. Then, they were heated at15 to 20° C. for two hours with stirring to complete the sulfonation.Next, the above reaction liquid was added in an iced water in such anamount that a total liquid volume was 450 parts. The aqueous liquid washeated, to which 48 parts of sodium chloride was added with stirring atabout 60° C. and they were stirred for one hour. The resultantprecipitates were filtered and washed with 50 parts of an aqueous 20%brine solution to obtain a wet cake.

This cake was again stirred with water in such an amount that a totalliquid volume was 300 parts. After a minor amount of insoluble matterwas removed by filtering, 52.5 parts of sodium chloride was added to themother liquid while stirring and then stirred for 30 minutes toprecipitate crystals. Further, 17.5 parts of sodium chloride was addedand stirred for 30 minutes. The resultant precipitates were filtered,washed with 50 parts of an aqueous 20% brine solution to obtain 32 partsof a sodium salt of the compound of the formula (5) as a wet cake.

(3) The wet cake obtained in the above (2) was stirred with 250 parts ofmethanol at room temperature for 30 minutes, filtered, washed with 200parts of methanol and dried, thereby 13.3 parts of the compound of theformula (5) was obtained as crystals of a bright yellowish red color.λ_(max)=531.0 nm (in aqueous solution)

solubility in water=100 g/L or higher

Example 3

To 46.3 parts of 96.6% sulfuric acid was added 53.7 parts of 31.7%fuming sulfuric acid while cooling with an iced water to prepare 100parts of 10% fuming sulfuric acid. Then, 9.2 parts of the compound ofthe formula (11) obtained in Example 2-(1) was added to the fumingsulfuric acid at room temperature over about 30 minutes. Then, they wereheated and reacted at 25 to 30° C. for 1.5 hours. Successively they wereheated and reacted at 60 to 70° C. for 1.5 hours to complete thesulfonation. Next, the above reaction liquid was added in an iced waterin such an amount that a total liquid volume was 300 parts. 60 parts ofsodium chloride was added to the aqueous liquid and they were stirredfor one hour. 600 parts of methanol was added to the aqueous solution toprecipitate crystals. After stirring for one hour, the precipitates werefiltered, washed with 300 parts of methanol and dried, thereby thecompound of the formula (12) was obtained as crystals of a red color.λ_(max)=529.6 nm (in aqueous solution)

solubility in water=100 g/L or higher

Example 4

(1) Into 100 parts of xylene, 26.4 parts of the compound of the formula(13):

0.6 part of sodium carbonate and 28.8 parts of ethyl benzoylacetate weresuccessively charged and heated. They were reacted at a temperature of140 to 143° C. for 4 hours, while water and ethanol produced weredistilled away together with xylene. After the reaction was completed,the resultant product was cooled with water, to which 150 parts ofmethanol was added, stirred for 30 minutes, filtered, washed with 200parts of methanol and hot water successively and dried, thereby 33.2parts of the compound of the formula (14) was obtained as needle-likecrystals of a red color.

(2) To 39.7 parts of 96.6% sulfuric acid was added 35.3 parts of 31.7%fuming sulfuric acid while cooling with an iced water to prepare 75parts of 6.5% fuming sulfuric acid. To fuming sulfuric acid undercooling with ice, 8.5 parts of the compound of the formula (14) obtainedin the above (1) was added at 15 to 20° C. over 15 minutes. Then, theywere reacted at 50 to 60° C. for 2 hours and successively at 70 to 80°C. for 2 hours. Next, the above reaction liquid was added in an icedwater in such an amount that a total liquid volume was 300 parts. 45parts of sodium chloride was added to the aqueous liquid with stirringat room temperature and they were stirred for one hour. The resultantprecipitates were filtered, washed with 50 parts of an aqueous 20% brinesolution and dried, thereby 11 parts of red crystals comprising themixture of 8.8 parts of the compound of the formula (15) and 2.2 partsof the compound of the formula (16).λ_(max)=527.8 nm (in aqueous solution)

solubility in water=100 g/L or higher

Example 5

(A) Preparation of Ink

A mixture having a composition as shown in the following Table 1 wasprepared. This mixture was filtered through a membrane filter of 0.45μm, thereby an aqueous ink composition for ink-jet recording of thepresent invention having a pH of 8 to 10 was obtained.

TABLE 1 Composition amount (parts) coloring matter obtained 3.0 in Ex. 1water + ammonium hydroxide 78.0 glycerol 5.0 urea 5.0N-methyl-2-pyrrolidone 4.0 IPA 3.0 butyl carbitol 2.0 total 100.0(Comparative Compositions)

For comparison, magenta ink compositions of Comparative Examples 1 and 2were prepared by using C.I. Acid Red 82 (Comparative Example 1) and C.I.Direct Red 227 (Comparative Example 2) and applying the compositionratio as shown in Table 1 so that each of the resultant compositions hadan optical density identical with that of the water-based magenta inkcomposition of the present invention.

(B) Ink Jet Printing

Using an ink-jet printer (trade name: PICTY 100L, NEC Corporation), anink-jet recording was made on a commercially available exclusive paper(PR-101 of Canon Inc.) and a commercially available exclusive paper (PMphotographic paper of Epson Corporation).

(C) Evaluation of Recorded Images

Hue (L*, a* and b* values) and color difference (ΔE*ab) before and aftereach test of the recorded images were determined using a colorimeter(GRETAG SPM 50 of GRETAG). Clarity (C*) of the recorded images wasevaluated according to the following equation:

 C*=((a*)²+(b*)²)^(1/2)

(i) Light Resistance Test

The resultant print was exposed for 20 hours using a carbon arc fademeter (Suga Test Instruments Co., Ltd.). A change before and after theexposure was judged in accordance with JIS blue scale. Simultaneously, acolor difference before and after the exposure was determined using theabove calorimeter.

(ii) Ozone Resistance Test

The resultant print was treated under conditions of a concentration of 4ppm and a temperature of 40° C. for 20 hours using an ozone weathermeter (Suga Test Instruments Co., Ltd.). A color difference before andafter the treatment was determined using the above calorimeter.

The results of the recorded images with respect to hue, clarity,difference in clarity (ΔC*), light resistance test and ozone resistancetest are shown in Table 1. The difference in clarity (ΔC*) is a valuewith reference to the hue resulting from the magenta ink composition ofthe present invention.

The evaluation results of the images recorded on the exclusive paper(PR-101 of Canon Inc.) are shown in Table 2. The evaluation results ofthe images recorded on the exclusive paper (PM photographic paper ofEpson Corporation) are shown in Table 3.

In the following tables, M1 represents the ink composition of Example 5,M2 represents the ink composition of Comparative Example 1 and M3represents the ink composition of Comparative Example 2.

TABLE 2 Evaluation results on exclusive paper (PR-101 of Canon Inc.)ozone light hue clarity resistance resistance L* a* b* C* ΔC* ΔE*abjudgement ΔE*ab M1 53.6 76.4 −3.26 76.5 ref 1.13 3-4 8.4 Grade M2 54.173.5 3.47 73.6 −3.8 13.80 4 3.4 Grade M3 54.8 75.3 −4.63 74.5 −2.0 12.002 33.9 Grade

TABLE 3 Evaluation results on exclusive paper (PM photographic paper ofEpson Corporation) ozone resis- light hue clarity tance resistance L* a*b* C* ΔC* ΔE*ab judgement ΔE*ab M1 53.8 77.1 −4.95 77.3 ref 2.82 3-4 9.6Grade M2 54.7 73.3 −0.56 73.3 −4.0 11.21 4 2.9 Grade M3 51.3 75.8 −10.7476.5 −0.8 14.32 2 47.8 Grade

As clear from Tables 2 and 3, the magenta ink composition of the presentinvention is superior, especially in ozone resistance, as compared withthe magenta ink compositions of Comparative Examples 1 and 2. Thus, themagenta ink composition of the present invention is very useful as amagenta ink giving prints excellent in long-period storage since printsresulting from the use of the magenta ink composition of the presentinvention are hardly affected by light and components such as gasescontained in an air even if they are stored or displayed for a longperiod.

As clear from Tables 2 and 3, the ink composition of the presentinvention has an almost ideal magenta color as compared with C.I. AcidRed 82 of the anthrapyridone color used in Comparative Example 1 sinceit gives a clear purple color having a good hue and clarity. And, it canbe said that the ink composition of the present invention is verysuperior ink composition since C* value is higher and clarity is better.

As clear from Tables 2 and 3, the ink composition of the presentinvention has higher light resistance as compared with C.I. Direct Red227 of Comparative Example 2 which is presently used as a magentacomponent in ink-jet inks. Therefore, prints resulting from the use ofthe ink composition of the present invention can be stored for a longperiod. Since the compound of the present invention has a solubility inwater of 100 g/L or higher, it is very excellent as a coloring matterfor ink-jet recording and an ink with a high concentration can beprepared.

Effect of the Invention

The anthrapyridone compound and the magenta ink composition containingit according to the present invention have characteristic that they havea high solubility in water so that they are satisfactorily filteredthrough a membrane filter during the preparation of an ink composition.And, the anthrapyridone compound is very safe for living body. Further,the ink composition of the present invention has good storage stabilityand therefore, it does not cause precipitation, change in physiologicalproperties, color change and the like even after stored for a longperiod. Since prints resulting from the use of the ink composition ofthe present invention as a magenta ink for ink-jet recording isexcellent in light resistance, moisture resistance and especially ozoneresistance, it is possible to use together with yellow, cyan and blackcolors so that each color excellent in ozone resistance, lightresistance and water resistance can be obtained by an ink-jet recordingmethod. Especially this advantage is remarkably exhibited on a recordingpaper having an ink receiving layer. In addition, the resultant printedsurface has a clear magenta color close to an ideal magenta color sothat a color tone over a wide visible light range can be obtained bycombining with other yellow and cyan inks. Accordingly, theanthrapyridone compound of the present invention is very useful as acolor in a magenta ink for ink-jet recording.

1. An anthrapyridone compound represented by the formula (1):

wherein R represents hydrogen atom or methyl group; X represents phenylgroup, phenoxy group or halogen atom; and n is an integer of 1 to 4, ora salt thereof.
 2. The anthrapyridone according to claim 1, wherein n isan integer of 2 to 4, or the salt thereof.
 3. The anthrapyridonecompound according to claim 2, wherein X represents phenyl group, or thesalt thereof.
 4. An anthrapyridone compound represented by the formula(2):

wherein X represents phenyl group, phenoxy group or halogen atom, or asalt thereof.
 5. An anthrapyridone compound represented by the formula(3):

wherein X represents phenyl group, phenoxy group or halogen atom, or asalt thereof.
 6. An anthrapyridone compound represented by the formula(4):

or a salt thereof.
 7. A water-based magenta ink composition comprisingthe anthrapyridone compound as defined in any one of claims 1 to 6, orthe salt thereof.
 8. The water-based magenta ink composition accordingto claim 7 comprising water and a water-soluble organic solvent.
 9. Awater-based magenta ink composition according to claim 7 or 8, whereinsaid composition is for ink-jet recording.
 10. An ink-jet recordingmethod, comprising jetting droplets of ink responding to a recordingsignal to record on a recording material wherein the ink comprise thewater-based magenta ink composition according to any one of claims 7 to9.
 11. An ink-jet recording method, comprising jetting droplets of inkset responding to a recording signal to record on a recording materialwherein the ink set comprises the water-based magenta ink compositionaccording to any one of claims 7 to 9 and a water-based cyan inkcomposition comprising a water-soluble metal phthalocyanine coloringmatter.
 12. An ink-jet recording method as defined in claim 10 or 11wherein the substrate to be recorded is a polyamide fibrous material andthe fibrous material is heat treated after the ink composition isapplied.
 13. An ink-jet recording method according to claim 10 or 11wherein the recording material is an information transmittance sheet.14. An ink-jet recording method according to claim 13 wherein theinformation transmittance sheet is a surface treated sheet.
 15. Anink-jet printer comprising a container containing a water-based magentaink composition according to any one of claims 7 to 9 and a containercontaining a water-based cyan ink composition comprising a water-solublemetal phthalocyanine coloring matter as an ink set.